The following U.S. Patent applications which are herein incorporated by reference are commonly owned by the Assignee of the present application:                (1) U.S. patent application Ser. No. 12/031,368 entitled Surgical Stapling Apparatus With Load-Sensitive Firing Mechanism to Geoffrey C. Hueil et al.;        (2) U.S. patent application Ser. No. 12/031,326, now U.S. Patent Publication No. 2009/0206130, entitled Surgical Stapling Apparatus With Interlockable Firing System to Steven G. Hall et al.;        (3) U.S. patent application Ser. No. 12/031,001, now U.S. Patent Publication No. 2009/0206133, entitled Articulatable Loading Units For Surgical Stapling and Cutting Instruments to Jerome R. Morgan et al.;        (4) U.S. patent application Ser. No. 12/030,980, now U.S. Patent Publication No. 2009/0206123, entitled Surgical Stapling Apparatus With Reprocessible Handle Assembly to Kevin R. Doll et al.;        (5) U.S. patent application Ser. No. 12/031,066, now U.S. Patent Publication No. 2009/0206129, entitled Surgical Stapling Apparatus With Articulatable Components to Kevin R. Doll et al.;        (6) U.S. patent application Ser. No. 12/030,974, now U.S. Patent Publication No. 2009/0206128, entitled Surgical Stapling Apparatus With Retractable Firing Systems to Geoffrey C. Hueil et al.        
Endoscopic surgical instruments are often preferred over traditional open surgical devices since a smaller incision tends to reduce the post-operative recovery time and complications. Consequently, significant development has gone into a range of endoscopic surgical instruments that are suitable for precise placement of a distal end effector at a desired surgical site through a cannula of a trocar. These distal end effectors engage the tissue in a number of ways to achieve a diagnostic or therapeutic effect (e.g., endocutter, grasper, cutter, staplers, clip applier, access device, drug/gene therapy delivery device, and energy device using ultrasound, RF, laser, etc.).
Known surgical staplers include an end effector that simultaneously makes a longitudinal incision in tissue and applies lines of staples on opposing sides of the incision. The end effector includes a pair of cooperating jaw members that, if the instrument is intended for endoscopic or laparoscopic applications, are capable of passing through a cannula passageway. One of the jaw members receives a staple cartridge having at least two laterally spaced rows of staples. The other jaw member defines an anvil having staple-forming pockets aligned with the rows of staples in the cartridge. The instrument commonly includes a plurality of reciprocating wedges which, when driven distally, pass through openings in the staple cartridge and engage drivers supporting the staples to effect the firing of the staples toward the anvil.
Different types of surgical staplers suitable for endoscopic applications are known. For example, one type of surgical stapler employs a staple cartridge. The staple cartridge typically supports a plurality of staples oriented on both sides of a longitudinally extending slot in the cartridge body that is adapted to receive a cutting member that is driven longitudinally therethrough. As the cutting member is driven through the cartridge slot, the staples are driven upward into the anvil portion of the instrument. The cutting member may be supported on a driven member that comprises a portion of the instrument apart from the cartridge. Examples of those types of devices are described in U.S. Pat. No. 6,905,057 to Jeffrey S. Swayze and Frederick E. Shelton, IV, entitled Surgical Stapling Instrument Incorporating a Firing Mechanism Having a Linked Rack Transmission and U.S. Pat. No. 7,083,075 to Jeffery S. Swayze, Frederick E. Shelton, IV, Kevin Ross Doll, and Douglas B. Hoffman entitled Multi-Stroke Mechanism With Automatic End of Stroke Retractions, the disclosures of which are herein incorporated by reference in their entireties.
Other types of surgical stapling instruments are configured to operate with disposable loading units (DLU's) that are constructed to support a cartridge and knife assembly therein. Such devices that are designed to accommodate DLU's purport to offer the advantage of a “fresh” knife blade for each firing of the instrument. An example of such surgical stapling instrument and DLU arrangement is disclosed in U.S. Pat. No. 5,865,361 to Milliman et al., the disclosure of which is herein incorporated by reference in its entirety.
Depending upon the nature of the operation, it may be desirable to adjust the positioning of the DLU or end effector of an endoscopic surgical instrument. In particular, it is often desirable to orient the DLU or end effector at an angle relative to the longitudinal axis of the shaft of the instrument. The transverse or non-axial movement of the DLU or end effector relative to the instrument shaft is often conventionally referred to as “articulation”. This articulated positioning permits the clinician to more easily engage tissue in some instances, such as behind an organ. In addition, articulated positioning advantageously allows a DLU or an endoscope to be positioned behind the end effector without being blocked by the instrument shaft.
Approaches to articulating a surgical stapling apparatus tend to be complicated by integrating control of the articulation along with the control of closing the end effector to clamp tissue and fire the end effector (i.e., stapling and severing) within the small diameter constraints of an endoscopic instrument. Generally, the three control motions are all transferred through the shaft as longitudinal translations. For instance, U.S. Pat. No. 5,673,840 to Schulze et al., the disclosure of which is herein incorporated by reference, discloses an accordion-like articulation mechanism (“flex-neck”) that is articulated by selectively drawing back one of two connecting rods through the implement shaft, each rod offset respectively on opposite sides of the shaft centerline. The connecting rods ratchet through a series of discrete positions.
Another example of longitudinal control of an articulation mechanism is U.S. Pat. No. 5,865,361 that includes an articulation link offset from a camming pivot such that pushing or pulling longitudinal translation of the articulation link effects articulation to a respective side. Similarly, U.S. Pat. No. 5,797,537 discloses a similar rod passing through the shaft to effect articulation. Still other examples of articulatable surgical stapling devices are disclosed in U.S. Pat. Nos. 6,250,532 and 6,644,532.
Due to the types firing systems commonly employed in connection with DLU's, the actuator arrangements for articulating the DLU must often generate high amounts of torque to bend the firing structure. This problem is exacerbated by the lack of available space for accommodating actuating devices that are large enough to generate those required forces. In addition, prior articulation arrangements required the clinician to use two hands to articulate the device.
Thus, there is a need for a surgical cutting and stapling instrument that is configured to accommodate DLU's and has improved articulation capabilities including the ability to articulate the instrument using one hand.